McKenzie Health Science 20 NAME:_________________

Lesson 15.2 Male Reproductive System Anatomy & PhysiologyWe will be skipping 15.1 as it is not in the SK curriculum

Objectives:1. Describe the anatomy of the male reproductive system.2. Explain how sperm are created and delivered for reproduction.3. Describe the phases of the male sexual response.

Saskatchewan Outcome:“I can analyze the anatomy and physiology of a healthy human”

Saskatchewan Indicators:“I can describe the anatomy (structure) and physiology (function) of the reproductive system”

Before this lesson, try to answer the following questions:

1. What are the primary and accessory male reproductive organs?

ANSWER:____________________________________________________________________

2. Where are sperm cells created? ANSWER:____________________________________________________________________

Key Terms: Bulbourethral glands Ductus deferens Ejaculation Epididymis Erection Gonads Penis Prostate gland Semen Seminal glands Seminiferous tubules sperm

References: Notes & handouts Textbook Pages: 535 – 539 Study Guide Pages: 225 – 227

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15.2 Male Reproductive System Anatomy and Physiology

The Male Reproductive System

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Location of Sperm Production & Development

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Reproduction 1:Human sexual reproduction involves the fusion of two types of gametes. A small, motile SPERM from the male and a large, stationary OVUM (or egg) from the female. These GAMETES contain half the number of chromosomes (23) compared to regular body cells (46). Fusion (or fertilization) of the ovum by the sperm results in the formation of a ZYGOTE which will develop into an EMBRYO and then a FETUS. Birth follows. This unit will consider these ideas and relationships in greater detail.

The Male Reproductive SystemThe primary male reproductive organs are called the TESTES. In the fetus, they develop in the abdominal cavity. Just before birth (or very soon after), the testes descend into an external sac called the SCROTUM which is located outside the body cavity. The testes are held outside the body cavity because sperm development requires a temperature of about 34° Celsius. Human body temperature (37° Celsius) is too warm.

Use figure 15.4 on p. 536 to label the following diagram.

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SpermatogenesisThe testes are divided into lobules, each of which contains 1 to 3 tightly coiled SEMINIFEROUS TUBULES. Special cells called SPERMATAGONIA within the seminiferous tubules undergo meiosis to produce the HAPLOID sperm. Millions of sperm are produced each day. The sperm in the seminiferous tubules are still immature and must undergo certain changes.

The EPIDIDYMIS are the areas of sperm storage and maturation.

The Epididymis join the VAS DEFERENS which connect to the URETHRA. The vas deferens also function in storing the sperm.

During intercourse, the sperm are forced from the epididymis and the vas deferens, through the URETHRA (out the URETHRAL OPENING) when muscular contractions called EJACULATIONS occur.

The path of sperm is:

SEMINIFEROUS TUBULES (TESTES) EPIDIDYMIS VAS DEFERENS URETHRA URETHRAL OPENING

SPERMATOGENESIS

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Seminiferous Tubule Cross Section

SPERMA sperm is a SINGLE CELL which consists of the following parts:

1. HEAD contains the highly condensed nucleus (23 chromosomes).2. ACROSOME adheres to the head (cap like), contains enzymes which facilitate penetration

of the egg. 3. MIDPIECE contains energy producing mitochondria.4. TAIL flagellum which propels the sperm forward.

Label the sperm below:

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SEMINAL FLUIDAt the time of ejaculation, approximately 400 million sperm leave the penis in the SEMINAL FLUID (also called semen). Sperm makes up only about 2% of the seminal fluid. The rest of the fluid consists of secretions from three glands.

1. SEMINAL VESICLES: lie at the base of the bladder and each has a duct that joins the vas deferens.

2. PROSTATE GLAND: a single doughnut shaped gland that surrounds the upper portion of the urethra just below the bladder.

3. COWPER’S GLANDS: pea sized glands that lie below the prostate on either side of the urethra.

The seminal fluid serves three important functions:

1. It has a slightly BASIC pH (7.5). This protects the sperm in the male urethra and female vagina, both of which are slightly acidic.

2. It contains the sugar FRUCTOSE which serves as an energy source for the swimming sperm.

3. It contains PROSTOGLANDINS which are chemicals that cause the female’s UTERUS to contract. These contractions propel the sperm towards the egg.

Complete the Lesson1. Read p. 535 - 539 in your textbook2. Make flashcards for A-J on Male Reproductive System Diagram (label on one side, function on other)

McKenzie Health Science 20 NAME:_________________

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Reproduction 2:

Regulation of Male Hormones

There are two GONADOTROPIC HORMONES released by the ANTERIOR PITUITARY gland. They are FOLLICLE STIMULATING HORMONE (FSH) and LEUTEINIZING HORMONE (LH). Both are named for their function in females, but exist in both sexes stimulating the appropriated gonads in each.

The HYPOTHALAMUS controls the secretions of the gonadotropic hormones and therefore controls the testes’ sexual function. The hypothalamus secretes GONADOTROPIC-RELEASING HORMONE (GnRH) which stimulates the ANTERIOR PITUITARY to produce and release LH and FSH.

The gonadotropic hormones have the following functions:

1. Follicle Stimulating Hormone (FSH) stimulates sperm production in the seminiferous tubules.

2. Leuteinizing Hormone (LH) stimulates testosterone production in the INTERSTITIAL CELLS .

** Interstitial cells are located between the seminiferous tubules in the testes.

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Negative Feedback:

Levels of testosterone are maintained at relatively constant levels by negative feedback.

High levels of testosterone inhibit the secretion of GnRH by the hypothalamus which stops the release of LH by the anterior pituitary.

The hormone INHIBIN is produced along with sperm in the seminiferous tubules. Inhibin blocks FSH secretion.

Functions of Testosterone:

1. Development and function of the primary sex organs.

2. Production of sperm. FSH causes the sperm-producing cells to take up testosterone. The testosterone stimulates their activity to make sperm.

At puberty, testosterone plays a number of important roles in males:

3. Maturation and growth of the testes and penis.

4. Development of SECONDARY SEXUAL CHARACTERISTICS. These include the growth of facial, underarm and pubic hair; growth of larynx and vocal cords (voice change), growth of muscles and greater muscular strength and secretions of oil and sweat glands (leads to body odor and acne).

5. Sex drive.

Complete the Lesson1. Complete #1-8, p. 5392. Study Guide pages 225 and 227 (handout)